"Crime is starting to pick up because a lot of people abandoned their houses. Two of my brother-in-laws' houses got ripped off," said Matt Purvis, owner of the Tin Shack Bakery, on Monday on the Big Island.
Purvis said the thieves are driving around during the day and breaking into homes, sometimes more than once.
Lava from Kilauea Volcano was about 70 yards from the closest home, the Hawaii County Civil Defense Agency said in its afternoon advisory Monday. The flow is moving about five yards per hour and had slowed down Monday afternoon.
Smoke could be a problem for people downwind, the agency said, while advising residents to stay inside.
"We can see the smoke and kind of a glow, especially at night," Purvis said.
After the lava flow engulfed the Pahoa cemetery, anxious residents prayed it did not kill off the small town.
"A lot of us are loading up on gas, getting generators in case the energy goes out," Mike Hale told CNN. "And we're checking to make sure the Internet stays up."
Hale owns Big Island Auto rentals in Pahoa, which has almost 950 residents.
With the lava consuming fields and flowing over fences, Hale took a precaution and moved 20 rental vehicles to Hilo.
"I'm just leaving a couple of (all-terrain vehicles) down on the side of my business. In case we're cut off," he said. "And if we are cut off, it will be a huge disaster."
The Bay Clinic was also taking extra steps, preparing a mobile medical unit to stage on the opposite side of the lava flow.
"We have not determined exactly where the mobile unit will go," said Harold Wallace, CEO of Bay Clinic. "It's going to be based on where the flow ends up, logistics, traffic and we'll talk to civil defense."
"If for some reason someone can't get to our clinic, we will be there with the mobile unit," he added. There's going to be people who need prescriptions and more."
Video shot by Hawaii County and provided to CNN by affiliate KHNL showed fires burning at the edge of the lava flow, consuming fields.
The civil defense agency said it sent workers door-to-door in the community on Sunday, informing them of the possible need to get out should conditions become too dangerous.
But most had already left, according to CNN affiliate KHON.
"Most people have vacated. They have moved out of their homes. There's only a few people left," the station quoted Hawaii County Civil Defense worker Franchesca Martin-Howe as saying.
The Hawaiian Volcano Observatory said Kilauea was still erupting at its summit and on the eastern side of the volcano.
"The whole town is really concerned and is nervous, and I am too. It's definitely concerning and the biggest is the unknown," Purvis said.